Long setting countdown time: 999 days, 23 hours, 59 minutes, and 59 seconds. Upgraded version with larger size. LCD screen size: 13.8 cm x 4 cm (5.4 x 1.6 in). Sounds an alarm for sixty seconds when the set time is reached. Includes clock function with 12-hour and 24-hour format options. Easy to set and operate. Two placement options: magnetic back and adjustable bracket. Suitable for various ocns such as vacations, weddings, baby tracking, retirement, meetings, and study sessions. To set the clock: Press and hold the CLOCK button until the hour digits flash. Use UP/START or DOWN to adjust the hour. Press CLOCK repeatedly to set minutes and seconds. Press CLOCK again to confirm. In clock mode, use the DOWN button to switch between 12-hour and 24-hour formats. To set the countdown time: Press and hold the SET button until a number flashes. Press SET repeatedly to navigate to the digit you wish to change. Use UP/START or DOWN to adjust the selected digit. Hold UP/START or DOWN for faster adjustment. Continue pressing SET until the display stops flashing. Press UP/START to begin or pause the countdown. To reset to zero, press and hold both UP/START and DOWN buttons simultaneously. Powered by 2 x CR2032 batteries (included). Color: Black. Material: ABS. Dimensions: Approximately 15.5 x 5.7 x 1.1 cm. Package Includes: 1 x Digital timer clock. Note: Other items not included. Lighting and display differences may cause slight color variations between the image and the actual item. Measurement may vary by +/- 1-3 cm.